Plant Science 150 2000 77 – 84
Stress treatments and ficoll for improving green plant regeneration in triticale anther culture
Sirkka Immonen , Jonathan Robinson
Plant Production Research, Crops and Soil, Agricultural Research Centre, Myllytie
10
, FIN-
31600
Jokioinen, Finland Received 22 June 1999; accepted 2 September 1999
Abstract
Anther culture of 10 winter triticale cultivars of diverse origin was studied. Two-week cold pretreatment was applied to all cultivars. In addition, cold pretreatment in combination with heat shock or mannitol starvation and prolonged cold stress of three
weeks were tested on some of the genotypes. Field and greenhouse conditions were compared for growing the mother plants. Anthers for stress treatment testing were cultured on solid W14. Ficoll-supplemented induction medium was tested with three
cultivars. A total of 378 green regenerants were analysed for DNA-ploidy with flow-cytometry. Morphological observations and seed-set were recorded for 317 plants grown to maturity. Large genotypic differences were noted between the cultivars. Seven out
of 10 cultivars exhibited a differential response to the treatments and it was possible to improve green plant production considerably by applying increased stress or by culture on a medium containing ficoll. Cold pretreatment complemented with heat
shock improved androgenetic response of the three cultivars tested. Prolonged cold pretreatment increased generally both the proportion of green plants and the proportion of spontaneous doubling. Morphological abnormalities, possibly caused by
aneuploidy and associated with loss of fertility, were observed in 23 of the plants. © 2000 Elsevier Science Ireland Ltd. All rights reserved.
Keywords
:
× Triticosecale; Stress treatment; Doubled haploid; Green plant regeneration; Plant morphology; Spontaneous doubling
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1. Introduction
Triticale × Triticosecale Wittmack can be considered to be a self-pollinated cereal, for which
doubled haploids DHs can be used effectively as a tool in breeding. DHs permit screening of quali-
tative characters due to inherent homozygosity. Increased selection efficiency of quantitative char-
acters follows from absence of dominance genetic variation and epistatic effects [1]. DHs can also be
useful in triticale breeding for fixing homozygosity after interspecific and intergeneric hybridization.
This represents one possible strategy for improv- ing local adaptation of triticale lines in, for
instance, environments characterised by a require- ment for good winter hardiness. Triticale is a
potential winter cereal for northern latitudes. Adapted local rye and wheat germplasm could be
used in triticale breeding programmes for such areas.
The use of DHs in triticale breeding pro- grammes is limited by the relatively low cost-effi-
ciency of anther culture [2]. In anther culture systems stress is of critical importance for blocking
gametophytic development and for triggering pol- len embryogenesis in competent microspores [3].
Other means for improving the yield of mi- crospore-derived green plants of cereals have in-
cluded culture in liquid medium supplemented with a buoyancy increasing component, ficoll type
400, to allow anthers and calli to float [4,5]. With wheat, Triticum aesti6um L. [6] and rye, Secale
cereale L. S. Immonen, unpublished data, the results have, however, been inconsistent.
Corresponding author. Tel.: +
358-3-41881; fax: +
358-3- 41882496.
E-mail address
:
sirkka.immonenmtt.fi S. Immonen 0168-945200 - see front matter © 2000 Elsevier Science Ireland Ltd. All rights reserved.
PII: S 0 1 6 8 - 9 4 5 2 9 9 0 0 1 6 9 - 7
In these experiments, we tested 10 winter trit- icale cultivars that had not previously been tested
for their anther culture ability. The selected culti- vars represented the genetic diversity of triticales
incorporated into the Finnish winter triticale breeding programme. The aims were to test vari-
ous stress treatments and culture media to im- prove the in vitro performance of triticale, to
evaluate this diverse material for use in DH-pro- duction and to obtain information on the quality
of the regenerants.
2. Materials and methods
